VOR Antenna

[GlennBob]

Anybody  recently installed the foil tape  VOR  antenna to the underside of the canard ?   Where to buy the materials.  How do you get the cable back to the fuselage without changing the shape of the wing ?   Also need a glideslope antenna and marker beacon.  Also  ELT  antenna.

If anybody has recently done this,  please contact me.  Thanks.

Glennbob

[Waiter]

I did the VOR on the bottom of the canard after I made and installed the canard/fuselage cover piece.

I dremeled out a small hole in the bottom of the canard/fuselage cover so a BNC connecter would fit in the hole. (Caution, Don't drill into the spar caps)

I ran the foil tape from the small hole, out along the bottom surface of the canard (as per plans). I connected the foil (using small wires) to the BNC connector, then used FLOX to embed the BNC connector into the hole in fuselage cover. I then laid up a BID strip over the foil tape.


The foil tape can be purchased from several places, McMasterCarr sells it

http://www.mcmaster.com/

Part Number 76555A712 is a 1/2 inch wide by 6 yards (18 ft) roll. Cost $11.17

I did a similiar thing for my "OLD" Loran. (I later used this antenna for the  Marker Beacon receiver). I ran the tape along the top surface of the gear leg. with a little aluminum bracket to hold the BNC connector.

Sorry, Can't help with the glideslope.  

Waiter

[GlennBob]

Thanks  Waiter ! !

This gives me some ideas on where to start ! !   :idea:

Glennbob

[GlennBob]

Waiter,

You're beautiful ! !   Thanks for the part #  for McMaster.   Looking it up,  I see that the price is less for Non-conductive adhesive.  My guess is we don't need adhesive at all since we're going to be flocking it in anyway so why not get the less expensive non-conductive adhesive.   Also, . .is  1/2 "  wide enough ?   I need to check the plans and see what they suggest.  Thanks again Waiter ! !    I'm  tickled ! !   ( some say pickled ).

Glennbob

[Waiter]

Glenn;

I would get the tape with the adhesive backing.  The adhesive will not effect the performance of the antenna. Also, any of the widths will be just fine, just make sure to cut the end at an angle as described below.

ALSO

When you cut the tape to the correct length thats specified in the plans., First, cut it at 90 deg, Now, to get the maximum frequency response from the antenna, we are going to make the antenna "electrically variable" by making another cut with a very sharp angle. (Instead of a 90 deg cut at the end, the end is going to be very sharp)

(Oh yah, make the pointy end the OUTSIDE end, not the end that is soldered to the connector)

EXAMPLE:

Measure back about 2 inches and place a mark on one edge of the tape. now cut from this mark, cut the tape lengthwise to the other edge, but at the end of the tape;

i.e. if you measured one edge of the tape, it would measure 21 inches, if you measure the other edge of the tape, it would measure 19 inches.

WHY DO THIS? RF Wavelengths tend to find their perfect antenna length, if its available. By making the the end of the foil pointy, you've provided many different antenna "lengths" that the RF can choose from.

An antenna thats operating into its "perfect" wavelength will be the most efficient.

Waiter

[Bruce Hughes]

Hi Glennbob

You asked "how to get the antenna back to the fuselage..."

Remember MUCH of the canard is INSIDE the fuselage, especially
the lower surface of the canard.

So much of the antenna, including the larger part in the center,
the coax connector, is already inside the fuselage.

Bruce Hughes

[GlennBob]

Waiter,

Thanks for the info on the "pointy" ends of the tape.  I understand what you're describing.  

I'm going to have to consult the plans about your earlier comment about not drilling through the spar caps.  I did not build this canard,  and although the rest of this bird is not painted,  the canard is and he's done a beautiful job on it.  I hate to wreck the paint job, but not much choice.  

I'm a little concerned about burying the terroids and such inside the canard wing and finding a way to get the cable back to the fuselage.

Bruce,

I already have a small antenna right in the middle underside of the canard, but the plans I got from RST engineering show the WHOLE  antenna on the outter ends of the canard and main wings. He shows several antennas.  Couple navs,  vor, and glideslope and I think coms.

I'm a little concerned about reception on an antenna that is right over my knees with all the metal of the instruments and mechanicals right under it.

The guy who built this canard did a beautiful job, but the antenna he installed is too small. Each leg is only about 8 1/2 inches.   RST said it was the size of a glideslope antenna, but the builder told me it was a VOR antenna so it's wrong.

Glennbob

P. S.  I have pics of this antenna on my canard avail @  ezskyboy@hughes.net

[Waiter]

You won't bury the toroids in the canard, They will be buried in the canard cover.  I wouldn't bring the antenna cable out of the canard, I would install (bury) a BNC connector in the cover. Then you can route the NAV cable to the canard, and simply connect it to the BNC connector thats embedded in the canard cover.

I'll see if I can get a photo of mine this weekend.  I'll post it on my web site under the canard construction photos.

http://www.iflyez.com/LongEZ_Construction_Photos_Canard.shtml


GLIDESLOPE - VOR

These can use the same antenna. You need to get a coupler that attaches to the antenna. Google VOR GLIDESLOPE COUPLER.

Here is one I found:

http://www.aircraftspruce.com/pdf/2007Individual/Cat07506.pdf


Waiter

[Waiter]

I posted a couple photos that show the BNC connector.

http://www.iflyez.com/LongEZ_Construction_Photos_Canard.shtml

Waiter

[GlennBob]

Waiter,

I hope you can stick with me until I understand this.  I see your picture of the BNC connector.  That part I get.  What I need to understand is how you get the wiring from the center of the "V" in the VOR antenna to the torroids and BNC connector.   ( Assuming the whole "V" is outside of the fuselage area ).

Also,  I don't want to use a coupler, because it will cut the signal by 30 %.  I need to install two seperate antennas.  One for the VOR and one for the Glideslope.  I think for the marker beacon,  I can simply run a wire down the longerons or something similar.

Glennbob

[Waiter]

I have a small drawing, but I can't scan it till later tonight.

Drill a 5/8 diameter hole in the bottom of the canard (maybe 1 inch deep). This hole will be where you'll install the BNC connector. Make sure it doesn't interfere with the F22 bulkhead AND DO NOT drill into the spar cap.

Cut your 2 foil tapes to the correct length. Remember, one end of the tape will be cut to a sharp point, the other end will just have a plain 90 cut.

You will be installing the foil tape on the bottom of the canard.

Remove the adhesive backing and lay down the two pieces of foil. The 90 degree end of the tape should butt up against the 5/8 hole, the tape is then stretch straight out toward the end of the canard, one tape on the left of the 5/8 hole, one tape on the right of the 5/8 hole.

You'll need a panel mount female BNC connector with the nut and a grounding solder tab that fits under the nut. Install the ground solder on the bottom of the BNC connector and tighten the nut.

Take two pieces of teflon covered wire, about two or three inches long. Solder one wire to the BNC center, and solder the other wire to the grounding tab.

Twist these two wires together.

Slide a toroid bead over the twisted pair.

Solder one wire end to one of the foils, and solder the other wire end to the other foil.

Put a piece of masking tape around the end of the BNC connector to keep FLOX from getting on it.

Mix up a small amount of flox and ffill the 5/8 hole 1/2 to 3/4 full.

Shove the twisted wires and torroieds into the hole, shove the BNC connector in so that only the connection end is sticking out.

wipe off excess flox, and let cure.

NOTE - At this time, you should also cover the foil with one layer of BID, then peel ply.

COUPLERS ***************************************************

First - A coupler is OK, Actually, you will cut the signal in 1/2 (3db) 1/2 goes to the VOR, the other 1/2 goes to the GS.

But I bet a weeks pay check that unless you set up the elaborate shop equipment, you would never be able to notice this 3 db loss.   Couplers are no problem and are used throughout the industry. I've installed dual VORs, dual GS, and even had a LORAN all on the same antenna.

Second - The VOR and GS antennas must be horizontally polarized (antenna flat as opposed to up and down)

ALSO, for optimum reception, the antenna must be at 90 degrees in relation to the transmitter. This is MANDATORY for GS. An antenna on the fuselage side would work great if your flying sideways.

Waiter

[GlennBob]

Waiter,

I am planning to use my VOR and Glideslope for IFR flight.  ( I live in Wisconsin with lots of IMC, not in AZ ).   Therefore I want to have as much VOR and Glideslope signal as I practically can.  Do you think I'm going overboard in not wanting to use a splitter ?  

When I am refering to the " outside " of the canard, . .I mean still on the canard,  but out on the lower horizontal portion of it but all on the starboard or all on the port side. (not on the fuselage).  This is what the sketch shows from the engineering dude that did the antennas on the Rutan birds. ( Including Voyager ).   He shows one on each of the wing extremedies.  One on the main wing (port) one on the canard (port) and one each on the other side (starboard).  I don't want to do more than I have to so if it'll work to use one antenna I guess that'd be easier, but I really want as much signal to each receiver as I can.

Glennbob

[walter]

Waiter,
So if the canard were inverted and I were to be looking down upon the two foil tapes, they would be 180 degrees between the two? The reason I ask is I believe I saw something about the two foil pieces forming a forward pointing "V".

[GlennBob]

Walter,

No, . . it's not 180  degrees between the two, . . I don't remember the exact angle but it's more like 120 or 140 degrees between the two.  Yes, . .it's a forward facing " V ".

Glennbob

P. S.  See the sketch in the plans.